Children's books are a great way to explore people and places.  When reading books with kids, it is a great idea to ask questions.  Keep in mind that the types of questions you ask are as important as the content of the question.  Here are a few suggestions to maximize the benefits of asking questions during reading time.

1. Ask a mix of literal, inferential, and evaluative questions.  Literal questions focus on the surface of the story.  The answers are stated directly in the text.  Answers to inferential level questions are found "between the lines" are require students to make inferences.  Evaluative questions take the reader beyond the book.  Answers require additional information that the students need to synthesize with the book.
2. Be careful how you word the questions.  Open ended questions allow for a wider range of responses and invite higher levels of participation.  Close ended questions (e.g., yes or no) limit thinking by restricting the possible responses.  They also minimize thinking because students either know or do not know the answer.  
3. Focus in the important features if the book.  Ask about the main characters, essential words, and key events.  If those are all well understood, explore secondary elements such as peripheral characters or words that are interesting but not essential to understanding the story.

Finally, I have watched many teachers ask questions that hint at answers, embed a bias, or include the answer within them.  Remember, questions are intended to promote thinking. As long as students are thinking, it does not matter as much as to whether students can answer any particular questions.  Be more concerned with whether your questions as a whole are directing students to consider about the important elements of stories.

Think of a book as a dark room.  The questions can be a lamp used to shine a light on what the students need to see.